In a large bowl, mix ground beef, pork, breadcrumbs, egg, garlic, onion, Parmesan cheese, Italian seasoning, red pepper flakes (if using), salt, and pepper until just combined.

Roll the mixture into 1.5-inch meatballs and set them aside.

Heat olive oil in a skillet over medium heat. Sear meatballs until golden brown on all sides, about 6-8 minutes.

In the same skillet, stir in the tomato paste and cook for 1-2 minutes.

Pour in the crushed tomatoes, then stir in heavy cream and additional Parmesan. Let it simmer to thicken for about 5-7 minutes.

Return the seared meatballs to the skillet and cover. Simmer on low heat for 15-20 minutes.

Garnish with fresh basil or parsley right before serving.